杰弗里斯金融集团股份有限公司美股招股说明书(2025-10-01版)

The information in this preliminary pricing supplement is not complete and may be changed without notice. This preliminary pricing supplement is not an offer tosell these securities, nor a solicitation of an offer to buy these securities, in any jurisdiction where the offering is not permitted.PRELIMINARY PRICING SUPPLEMENTSUBJECT TO COMPLETION, DATED October 1, 2025 (to Prospectus Supplement datedMay 12, 2023 and Prospectus datedMay 12, 2023) $Jefferies Jefferies Financial Group Inc.Senior Fixed Rate 10 Year Callable Notes due October 20, 2035 We have the right to redeem the Notes, in whole or in part, on each Optional Redemption Date. Subject to our redemption right, the amount of interest payable on the Notes will be 5.50%from and including the Original Issue Date to, but excluding, the stated maturity date (October 20, 2035). All payments on the Notes, including the repayment of principal, are subject to thecredit risk of Jefferies Financial Group Inc. Issuer:Title of the Notes:Aggregate Principal Amount:Issue Price:Pricing Date:Original Issue Date:Maturity Date:Interest Accrual Date:Interest Rate:Interest Payment Period: Interest Payment Dates:Day-Count Convention:Redemption: Optional Redemption Dates:Specified Currency:CUSIP/ISIN:Book-entry or Certificated Note:Business Day: Agent:Trustee:Use of Proceeds:Listing:Conflict of Interest: The Notes will be our senior unsecured obligations and will rank equally with our other senior unsecured indebtedness. Public Offering Price(1)Underwriting Discounts and Commissions(1)Proceeds to Jefferies Financial Group Inc. (Before Expenses) (1) The Agent may purchase the Notes for sale to certain fee-based advisory accounts and may forgo some or all of their underwriting discounts and commissions. The price for investorspurchasing the Notes in these accounts will be reduced by an amount that will be up to such forgone underwriting discounts and commissions. JefferiesPricing supplement dated, 2025.You should read this document together with the related prospectus and prospectus supplement,each of which can be accessed via the hyperlinks below, before you decide to invest.Prospectus supplement dated May 12, 2023 and Prospectus dated May 12, 2023 PRICING SUPPLEMENT SPECIAL NOTE ON FORWARD-LOOKING STATEMENTSRECENT DEVELOPMENTSTHE NOTESRISK FACTORSMATERIAL UNITED STATES FEDERAL INCOME TAX CONSEQUENCESSUPPLEMENTAL PLAN OF DISTRIBUTIONCONFLICT OF INTERESTLEGAL MATTERSEXPERTS You should rely only on the information contained in or incorporated by reference in this pricing supplement and theaccompanying prospectus and prospectus supplements. We have not authorized anyone to provide you with differentinformation. We are not making an offer of these securities in any state where the offer is not permitted. You should notassume that the information contained in this pricing supplement or the accompanying prospectus is accurate as of any datelater than the date on the front of this pricing supplement. SPECIAL NOTE ON FORWARD-LOOKING STATEMENTS This pricing supplement and the accompanying prospectus and prospectus supplement contain or incorporate by reference “forward-looking statements” within the meaning of the safe harbor provisions of Section 27A of the Securities Act of 1933 (the “Securities Act”)and Section 21E of the Securities Exchange Act of 1934. These forward-looking statements are not statements of historical fact andrepresent only our belief as of the date such statements are made. There are a variety of factors, many of which are beyond our control,which affect our operations, performance, business strategy and results and could cause actual reported results and performance todiffer materially from the performance and expectations expressed in these forward-looking statements. These factors include, but arenot limited to, financial market volatility, actions and initiatives by current and future competitors, general economic conditions, controlsand procedures relating to the close of the quarter, the effects of current, pending and future legislation or rulemaking by regulatory orself-regulatory bodies, regulatory actions, and the other risks and uncertainties that are outlined in our Annual Report on Form 10-K forthe fiscal year ended November 30, 2024 filed with the U.S. Securities and Exchange Commission, or the SEC, on January 28, 2025(the “Annual Report on Form 10-K”) and in our Quarterly Reports on Form 10-Q for the quarterly periods ended February 28, 2025 andMay 31, 2025 filed with the SEC on April 9, 2025 and July 9, 2025, respectively. You are cautioned not to place undue reliance onforward-looking statements, which speak only as of the date they are made. We do not undertake to update forward-looking statementsto reflect the impact of circumstances or events that arise after the date of the forward-looking statements. Table of Contents RECENT DEVELOPMENTS On September 29, 2025, Jefferies Financial Group Inc. announced its financial resu